This invention is directed toward the maintenance of rotating cutting tool assemblies that use bullet shaped cutting bits, typically seated in pocket holders which are affixed to the surface of a rotating member, such as an auger or other drill head apparatus. This tool extracts the rotatable cutting bits from the bit pockets.
Bullet bits are the teeth of these rotating cutting assemblies and wear out at different rates depending on the particular substrate being cut. These bullet bits wear and must be replaced to avoid uneven cutting, vibrations, damage to the pockets, and damage to the other components of the auger assembly.
These seated bullet cutting bits have an exposed annular groove near the surface of the bit pocket, the pocket holds the bullet bit at an angle to the surface of the auger head, and the pocket has an open back such that the shank of the bullet bit is visible from the back of the pocket holder.
U.S. Pat. No. 3,752,515, and U.S. Pat. No. 6,851,758, disclose a solution to the problem of bit retaining, and the mechanism for keeping the bullet bit seated in the pocket while allowing it to rotate, via a collar which is wrapped around the shank of the cutting bit, and engages an internal annular ring within the pocket holder. Heretofore, the art, such as U.S. Pat. No. 6,478,383, has focused almost exclusively on bit pocket design and retainer methods rather than safe bit extraction tools. Removing these bullet bits is currently performed by either punching the back of the shank through the open back of the pocket holder, ejecting the bullet bit, or by sliding a two pronged fork (referred to as a ‘crow's foot’) across the bits' external annular groove, at the surface of the pocket, and prying the bit out of the pocket.
Consistent with this articulation of the state of the art in bit extraction, is the recital in paragraph nine of the Background of the Invention section of, U.S. Pat. No. 6,851,758; the state of the art in bit extraction is dynamic punching. Currently drillers hammer-punch the bit out from the back of the pocket holder, or pry the bit out with a “crow's foot” fork ended pry bar, when the back of the pocket is not accessible. These are the only two means for bit extraction until now. These dynamic, awkward, and often unsafe methods are often ineffective leading to many hours of lost productivity, equipment damage, and often operator injury.
Depending on the size of the auger head, and the pocket holder arrangement, some bits cannot be punched out because the back of the pocket holder is not easily accessible. Often the angle of the bit, and the difficulty in prying the bit out, leads to hours of lost productivity, injuries resulting from mishaps with hammers, forks, and punches, and when operators cannot remove the bit, they often continue to drill with unevenly worn bits, which can seriously damage the drilling rig and lead to other injuries and equipment damage.